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\begin{frame}
\frametitle{Example}

\booksexample
\medskip\pause

\only<2>{
\begin{itemize}
\item The ISBN uniquely identifies a book. Thus
\begin{talign}
\sql{ISBN} \to \sql{TITLE}, \sql{PUBLISHER}
\end{talign}
Equivalently
\begin{itemize}
\item $\sql{ISBN} \to \sql{TITLE}$, and
\item $\sql{ISBN} \to \sql{PUBLISHER}$
\end{itemize}
\end{itemize}
}
\only<3>{
\begin{itemize}
\item A book may have many authors. Thus
\begin{talign}
\sql{ISBN} \to \sql{AUTHOR}
\end{talign}
\end{itemize}
}
\only<4>{
\begin{itemize}
\item One author can write many books, thus
\begin{talign}
\end{talign}

Although it happens to hold in the above database state.
\end{itemize}
}
\only<5>{
\begin{itemize}
\item
There may be books with the same title but different authors and different publishers.
So
\begin{talign}
\sql{TITLE}
\end{talign}
determines no other attributes.
\end{itemize}
}
\only<6>{
\begin{itemize}
\item Every book has only one first (second, third, \dots)
author. Thus\vspace{-1ex}
\begin{talign}
\sql{ISBN}, \sql{NO} \to \sql{AUTHOR}
\end{talign}
\end{itemize}
}
\only<7>{
\begin{itemize}
\item
At first glance, the author of any given book is also
uniquely assigned a position in the authorship sequence.
\begin{talign}
\end{talign}
However, violated by an author list like Smith \& Smith.
\end{itemize}
}
\only<8>{
\begin{itemize}
\item What about the functional dependency
\begin{talign}
\end{talign}
Authorship sequence might change in a new edition of a book!
\end{itemize}
}
\only<9>{
\begin{goal}{}
During database design, \emph{only unquestionable conditions should be used
as functional dependencies}.
\end{goal}
\begin{itemize}
\item Database normalization \emph{alters the table structure} depending
on the specified functional dependencies.\\
\remark{Later hard to change: needs creation/deletion of tables!}
\end{itemize}
}
\vspace{10cm}
\end{frame}